The long-range goal of these investigations is to elucidate the function(s) of carnitine octanoyltransferase of microsomes (endoplasmic reticulum), mitochondria and peroxisomes as well as the function(s) of microsomal and peroxisomal carnitine acetyltransferase in liver and other tissues. Both transferases occur in mitochondria, microsomes, and peroxisomes of rat and pig liver. One goal of the proposed research is to purify and characterize mitochondrial carnitine octanolytransferase and microsomal carnitine acetyltransferase and determine if these enzymes are the same or different than those that occur in the other organelles. Standard methods as well as affinity chromatography involving coenzyme A and/or carnitine as the bound substrate will be used for purification of the enzymes. The amount and distribution of the transferases in organelles of different tissues and the developmental pattern of the acetyl- and octanoylcarnitine acyltransferase in selected tissues will be determined. New methodology for identification and quantitation of water-soluble and water-insoluble acylcarnitines is proposed. These techniques will be used to identify the acylcarnitines that occur in tissues and then will be used to determine the levels of these metabolites in tissues that are in different metabolic states such as fed and fasted states and alloxan- induced diabetes. The distribution of the various transferases in tissues, their developmental pattern, and the level and changes in levels of acylcarnitines due to creation of specific metabolic states will be used to ascertain the multiorganelle function(s) of the short-and medium-chain transferases.